Adolescence is a critical period for the development of substance use disorders. There is a clear need for novel substance use preventions for youth, particularly developmentally-informed interventions rooted in basic science findings (NIDA, 2010). Significant basic research indicates parent stress as a risk factor for adolescent substance use and HIV risk behaviors. This risk may be exacerbated in low-income families who face multiple chronic stressors. Mindfulness-based stress reduction (MBSR) is an empirically-supported treatment that reduces stress in adults. However, the potentially powerful effects of MBSR on parenting stress and adolescent outcomes have not been tested. The goal of the proposed study is to develop and test a parenting-focused version of MBSR to reduce parent stress and prevent adolescent substance use and HIV risk behaviors in low-income urban families. We hypothesize that parenting-focused MBSR (P-MBSR) will decrease parent stress, improve parenting behavior and the parent-child relationship, decrease youth bio-behavioral arousal, and prevent risk for substance use and HIV risk behaviors. In this early-career investigator initiated project, 120 parents of 12-14 year olds reporting high parenting stress will be recruited at a child guidance clinic serving a low-income urban community. Parents will be randomly assigned to receive either an 8 week P-MBSR intervention at the clinic (based on the MBSR intervention implemented at the Yale Stress Center by Dr. Sinha, co-I) or to a parenting advice control group. At pre- and post-intervention, adaptive and mindful parenting behaviors and parent and youth bio-behavioral stress responses will be measured using a cutting-edge laboratory paradigm that models parent-adolescent interactions and youth emotional and physiological responses to interactions (developed by Dr. Chaplin, PI; Chaplin et al., 2012). Before, after, and at 6 months and 1 year post-intervention, we will collect questionnaire, clinical interview, and biological measures of parent stress, stress-related disorders, parenting, parent-child closeness, and adolescent intentions and expectancies for and engagement in substance use and HIV risk behaviors (e.g., unprotected sex). We will test intervention effects with HLM analyses. Based on our pilot finding that MBSR decreased stress in adults, we expect that P-MBSR will reduce parent stress, increase adaptive and mindful parenting and close parent-adolescent relationships, decrease adolescent physiological and emotional responses to parent interactions and prevent youth substance use and risky sex. If hypotheses are supported, the study will provide: 1. Initial feasibility and efficacy data for P-MBSR, 2. Pilot effect size data for a R01 application to conduct a longer-term RCT of P-MBSR, 3. Evidence of relevance and acceptability of P- MBSR in a real-world setting, and 4. Longitudinal data on substance use in at-risk youth. P-MBSR could be a cost-effective strategy to reduce stress and stress-related disorders in at-risk adults and at the same time prevent drug use and risk behavior in their children.